Flexible, cannulated implants for the hand and foot and methods of implanting flexible implants

ABSTRACT

A flexible, cannulated bone implant includes a proximal stem having a proximal end, a distal end, and a proximal conduit extending from the proximal end to the distal end of the proximal stem, a distal stem having a proximal end, a distal end, and a distal conduit extending from the proximal end to the distal end of the distal stem, and a flexible hinge interconnecting the distal end of the proximal stem with the proximal end of the distal stem for allowing the proximal and distal stems to flex relative to one another. The implant includes a proximal stem protective tube disposed within the proximal conduit of the proximal stem, and a distal stem protective tube disposed within the distal conduit of the distal stem. An elongated pin extends through the distal stem protective tube disposed within the distal stem and the proximal stem protective tube disposed within the proximal stem for securing the implant to bone.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present patent application claims benefit of U.S. ProvisionalApplication No. 62/615,781, filed Jan. 10, 2018, and U.S. ProvisionalApplication No. 62/614,527, filed Jan. 8, 2018, the disclosures of whichare hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present patent application is generally related to surgicalimplants, and is more specifically related to implants for hand digitalimplantation and treating hammertoe deformities.

Description of the Related Art

A hammer toe is a deformity that causes a toe to bend or curl downwardinstead of pointing forward. This deformity can affect any toe on afoot. It most often affects the second, third, and fourth toe.

Hammer toe most frequently results from wearing poorly fitting shoesthat can force the toe into a bent position, such as excessively highheels or shoes that are too short or narrow for the foot, therebydisrupting the muscle tendon balance of the proximal interphalangealjoint (hereinafter referred to as “the PIP joint”) and themetatarsophalangeal joint (hereinafter referred to as “the MTP joint”).Having the toes bent for long periods of time can cause the muscles inthem to shorten, resulting in the hammer toe deformity. This is oftenfound in conjunction with bunions or other foot problems (e.g., a bunioncan force the big toe to turn inward and push the other toes). It canalso be caused by muscle, nerve, or joint damage resulting fromconditions such as osteoarthritis, rheumatoid arthritis, stroke,Charcot-Marie-Tooth disease, complex regional pain syndrome or diabetes.Hammer toe deformities can also be found in Friedreich's ataxia (GAAtrinucleotide repeat). https://en.wikipedia.org/wiki/Hammer_toe.

In many cases, conservative treatment consisting of physical therapy,padding techniques, and new shoes with soft, spacious toe boxes isenough to resolve the condition. In more severe or longstanding caseshammertoe surgery may be necessary to correct the deformity. In someinstances, an implant is placed into the toe to correct the hammer toedeformity.

There have been a number of efforts directed to providing implants fortreating hammer toe deformities. For example, Wright Medical Group N.V.of Memphis, Tenn. sells implants and implant kits for treating hammertoe deformities under the trademark PHALINX™. Some of the implants arecannulated so that Kirschner wires may be passed through cannulatedopenings for securing implants to bone. Other implants have a ten degreeangle designed into the implant so that a toe carrying the implant mayhave a slight bend instead of being held in a permanent, straightorientation. In any event, the implants are rigid and do not flex, whichresults in toes being locked in position and unable to post-operativelyflex and bend. Moreover, conventional implants do not address both theMTP joint contracture correction while allowing flexion at the PIPjoint.

Thus, there remains a need for hammertoe implants that allow toes topost-operatively flex and bend while also allowing surgical correctionat the MTP joint. There also remains a need for hammertoe implantshaving flexible hinges and/or flexible joints so that the proximal anddistal stems of the implant may flex and move relative to one anotherafter being implanted in the respective proximal and middle phalanxes ofa toe. In addition, there remains a need for flexible, cannulatedimplants for use in the hand or for being implanted between to bones ofa human or animal patient.

SUMMARY OF THE INVENTION

In one embodiment, a flexible, cannulated hammertoe implant preferablyprovides for surgical correction with stabilization of a hammer toedeformity at a metatarsal phalangeal joint, while allowing flexion atthe proximal interphalangeal jointpost-operatively.

In one embodiment, a flexible, cannulated implant is used for handdigital implantation.

In one embodiment, a flexible, cannulated implant is used between twobones of a human or animal patient, whereby the implant allows forpost-operative flexibility between the two bones.

The flexible implant may be made of medical grade biocompatiblematerials that are typically used for making surgical implants includingmetals (e.g., titanium, stainless steel, alloys thereof), polymers(e.g., plastics, medical grade silicone elastic polymers), andcombinations of metals and polymers.

In one embodiment, a hammertoe implant has a central cannulated corethat allows for the placement of an elongated pin (e.g., a Kirschnerwire), which may be retrograded across the metatarsal phalangeal jointto stabilize the surgical correction of the soft tissue contracture.

In one embodiment, a hammertoe implant has a proximal stem that isadapted for placement into the proximal phalanx and a distal stem thatis adapted for placement into the middle phalanx. In one embodiment, theproximal stem is longer than the distal stem.

In one embodiment, a hammertoe implant may be a unitary structure orbody having a flexible hinge that is located between and interconnectsthe proximal stem of the implant and the distal stem of the implant. Theflexible hinge is preferably thinner than the proximal and distal stemsto provide a more flexible region of the implant. In one embodiment, theflexible hinge may be reinforced with a strut system or one or morereinforcing elements to prevent fracturing of the implant at the hinge.In one embodiment, the reinforcing elements may be made of fabric,fabric mesh, polyester mesh, fabric material sold under the trademarkDACRON, or other fabrics that are compatible with the polymers orplastics used to make the unitary body of the implant.

In one embodiment, a hammertoe implant has a cannulated central shaftthat allows for the placement of an elongated pin (e.g., a Kirschnerwire) for stabilization of the digital deformity post-operatively at theMTP joint. In one embodiment, the elongated pin (e.g., a Kirschner wire)positioned within the cannula may be removed after 4-6 weekspost-operative to allow for flexion at the proximal interphalangealjoint. The elongated pin may have different diameters. In oneembodiment, the elongated pin has diameters ranging from 0.035-0.062inches.

In one embodiment, a flexible bone implant preferably includes aproximal stem having a proximal end, a distal end, and a proximalconduit extending from the proximal end to the distal end of theproximal stem, a distal stem having a proximal end, a distal end, and adistal conduit extending from the proximal end to the distal end of thedistal stem, and a flexible hinge interconnecting the distal end of theproximal stem with the proximal end of the distal stem for allowing theproximal and distal stems to flex relative to one another. In oneembodiment, the flexible hinge may have one or more reinforcing strutsor reinforcing elements to prevent fracturing of the implant at theflexible hinge.

In one embodiment, a flexible bone implant preferably includes aproximal stem protective tube disposed within the proximal conduit ofthe proximal stem, and a distal stem protective tube disposed within thedistal conduit of the distal stem.

In one embodiment, an elongated pin extends through the distal stemprotective tube disposed within the distal stem and the proximal stemprotective tube disposed within the proximal stem for securing theimplant to bone.

In one embodiment, the proximal stem, the distal stem, and the flexiblehinge comprise a unitary structure made of polymer materials such assilicone elastic polymers and/or plastics.

In one embodiment, the proximal stem protective tube and the distal stemprotective tube are made of metal such as biocompatible metals,titanium, titanium alloys, stainless steel, and/or stainless steelalloys.

In one embodiment, the elongated pin may be bone pins or Kirchner wiresof different sizes.

In one embodiment, the proximal stem has a flat top surface, a flatbottom surface, and flat side surfaces that define a proximal stemstructure having a substantially square or rectangular shapedcross-section.

In one embodiment, the distal stem has a flat top surface, a flat bottomsurface, and flat side surfaces that define a distal stem structurehaving a substantially square or rectangular shaped cross-section.

In one embodiment, the flexible hinge preferably includes a top sidedefined by a first sloping sidewall at the distal end of the proximalstem, a second sloping sidewall at the proximal end of the distal stemthat opposes the first sloping sidewall, and a flat top surface thatextends between and interconnects lower ends of the first and secondsloping sidewalls.

In one embodiment, the first sloping sidewall, the second slopingsidewall and the flat top surface define a V-shaped top side of theflexible hinge having a truncated, flat apex.

In one embodiment, the proximal conduit extending through the proximalstem defines a first opening in the first sloping sidewall, and thedistal conduit extending through the distal stem defines a secondopening in the second sloping sidewall that is aligned with the firstopening in the first sloping sidewall.

In one embodiment, the flexible implant is normally urged into astraight configuration in which the proximal and distal conduits extendalong a common axis.

In one embodiment, the flexible implant is moveable into a flexedconfiguration in which the proximal and distal conduits extend alongdifferent axes that define an angle.

In one embodiment, the flexible hinge may also include a bottom sidedefined by a first bottom side sloping sidewall at the distal end of theproximal stem, a second bottom side sloping sidewall at the proximal endof the distal stem that opposes the first bottom side sloping sidewall,and a flat bottom surface that extends between and interconnects upperends of the first and second bottom side sloping sidewalls.

In one embodiment, the first bottom side sloping sidewall, the secondbottom side sloping sidewall, and the flat bottom surface define aV-shaped bottom side of the flexible hinge having a truncated, flatapex.

In one embodiment, a flexible implant may include a reinforcing elementembedded within the flexible hinge or covering one or more surfaces ofthe flexible hinge. In one embodiment, the reinforcing element may be amesh, such as a polyester mesh. In one embodiment, the polyester meshmay be made of the polyester fabric sold under the trademark DACRON. Inother embodiments, other reinforcing fabrics may be used instead ofpolyester fabrics so long as they are compatible with the polymer orplastic materials used to make the implant.

In one embodiment, a flexible bone implant preferably includes aunitary, polymer body including a proximal stem, a distal stem, and aflexible hinge located between the proximal and distal stems. In oneembodiment, the proximal stem has a proximal end, a distal end, and aproximal conduit extending from the proximal end to the distal end ofthe proximal stem. In one embodiment, the distal stem has a proximalend, a distal end, and a distal conduit extending from the proximal endto the distal end of the distal stem. In one embodiment, the flexiblehinge interconnects the distal end of the proximal stem with theproximal end of the distal stem for allowing the proximal and distalstems to flex relative to one another.

In one embodiment, a proximal stem protective tube made of metal isdisposed within the proximal conduit of the proximal stem, and a distalstem protective tube made of metal is disposed within the distal conduitof the distal stem.

In one embodiment, the flexible hinge includes a top side defined by afirst sloping sidewall at the distal end of the proximal stem, a secondsloping sidewall at the proximal end of the distal stem that opposes thefirst sloping sidewall, and a flat top surface that extends between andinterconnects lower ends of the first and second sloping sidewalls.

In one embodiment, the flexible implant may include one or morereinforcing elements in contact with the flexible hinge. The reinforcingelement may be a reinforcing fabric embedded within the flexible hinge,and/or covering one or more of the top and bottom surfaces of theflexible hinge for enhancing the durability of the hinge during repeatedflexing and bending.

In one embodiment, the proximal conduit extending through the proximalstem defines a first opening in the first sloping sidewall, and thedistal conduit extending through the distal stem defines a secondopening in the second sloping sidewall that is aligned with the firstopening in the first sloping sidewall.

In one embodiment, an elongated pin such as a Kirchner wire extends inseries through the proximal stem protective tube disposed within thedistal stem, the first opening in the first sloping sidewall, the secondopening in the second sidewall, and the proximal stem protective tubedisposed within the proximal stem.

In one embodiment, the implant is a unitary, polymer body that normallyurges the flexible implant into a straight configuration in which theproximal and distal conduits are in alignment with one another andextend along a common axis. The flexible implant is moveable into aflexed configuration in which the proximal and distal conduits are notin alignment with one another and extend along different axes thatdefine an angle.

In one embodiment, a method of implanting a flexible bone implant inbone preferably includes providing a flexible bone implant including aproximal stem having a proximal end, a distal end, and a proximalconduit extending from the proximal end to the distal end of theproximal stem, a distal stem having a proximal end, a distal end, and adistal conduit extending from the proximal end to the distal end of thedistal stem, and a flexible hinge interconnecting the distal end of theproximal stem with the proximal end of the distal stem.

In one embodiment, a method includes forming a distal opening in adistal bone and inserting the distal stem of the flexible bone implantinto the distal opening, and forming a proximal opening in a proximalbone and inserting the proximal stem into the proximal opening so thatthe flexible hinge is located between the proximal and distal bones.

In one embodiment, a method includes flexing the flexible bone implantso that the proximal and distal conduits extend along axes that definean angle, and inserting a distal end of an elongated pin into an openingat a proximal end of the distal conduit and advancing the elongated pindistally through the distal stem and the distal bone so that a distalend of the elongated pin projects out of the end of a toe, finger, oranimal appendage.

In one embodiment, a method includes placing the flexible bone implantin a straight configuration so that the proximal and distal conduitsextend along a common axis, and inserting a proximal end of theelongated pin into the proximal conduit and advancing the elongated pinproximally (i.e., retrograding the elongated pin) through the proximalstem and the proximal bone.

In one embodiment, a method includes before the inserting the elongatedpin into the distal and proximal conduits, disposing a proximal stemprotective tube within the proximal conduit of the proximal stem, anddisposing a distal stem protective tube within the distal conduit of thedistal stem.

In one embodiment, the flexible bone implant is a unitary structure madeof polymer materials and the protective tubes are made of biocompatiblemetals.

In one embodiment, the implant may be made of a polymer or plasticmaterial with the proximal and distal conduits being formed in therespective proximal and distal stems. In one embodiment, the proximaland distal conduits may be hardened by using a polymer or plastic layerthat is harder than the polymer or plastic material utilized to make theproximal stem, the distal stem and the flexible hinge of the implant. Inone embodiment, the proximal and distal conduits may be treated with achemical that hardens the conduits for preventing the elongated pin fromdamaging the surfaces of the conduits as the elongated pin passesthrough the conduits. In one embodiment, when the proximal and distalconduits are hardened, it may not be necessary to place metal protectivetubes within the conduits.

These and other preferred embodiments of the flexible, cannulatedimplants disclosed herein and methods of implanting the disclosedimplants in a patient will be described in more detail herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a side view of a flexible implant including a proximalstem, a distal stem, and a flexible hinge that interconnects theproximal and distal stems, in accordance with one embodiment of thepresent patent application.

FIG. 1B shows a top plan view of the flexible implant shown in FIG. 1A.

FIG. 2 shows a magnified view of the flexible hinge of the flexibleimplant shown in FIG. 1A.

FIG. 3A shows a side view of the implant of FIG. 1A with an elongatedpin extending through the proximal and distal stems, in accordance withone embodiment of the present patent application.

FIG. 3B shows a top plan view of the implant and the elongated pin shownin FIG. 3A.

FIG. 4A shows a cross-sectional side view of the bones of a toe with theflexible implant and elongated pin of FIG. 3A implanted in the osseousstructure of the toe, in accordance with one embodiment of the presentpatent application.

FIG. 4B shows another cross-sectional side of the flexible implant andthe elongated pin shown in FIG. 4A.

FIG. 5A shows a cross-sectional top plan view of the flexible implantand the elongated pin of FIG. 4A.

FIG. 5B shows another cross-sectional top plan view of the flexibleimplant and the elongated pin shown in FIG. 5A.

FIG. 6A shows a cross-sectional side view of a method of treating ahammertoe deformity, in accordance with one embodiment of the presentpatent application.

FIG. 6B shows a cross-section top plan view of the method step shown inFIG. 6A.

FIG. 7A shows a first step of a method of implanting a flexible implantin a toe, in accordance with one embodiment of the present patentapplication.

FIG. 7B shows a second step of a method of implanting a flexible implantin a toe, in accordance with one embodiment of the present patentapplication.

FIG. 7C shows a third step of a method of implanting a flexible implantin a toe, in accordance with one embodiment of the present patentapplication.

FIG. 8 shows a cross-sectional side view of a flexed toe having theflexible implant of FIG. 7C, in accordance with one embodiment of thepresent patent application.

FIG. 9 shows an exploded view of a flexible, cannulated implant having aproximal stem, a proximal protective tube insertable into a proximalconduit of the proximal stem, a distal stem, a distal protective tubeinsertable into a distal conduit of the distal stem, and a flexiblehinge that interconnects the proximal and distal stems, in accordancewith one embodiment of the present patent application.

FIG. 10 shows the flexible, cannulated implant of FIG. 9 with theproximal protective tube inserted into the proximal stem and the distalprotective tube inserted into the distal stem of the implant.

FIG. 11 shows the flexible, cannulated implant of FIG. 10 with anelongated wire extending through the proximal and distal stems of theimplant, in accordance with one embodiment of the present patentapplication.

FIG. 12A shows a flexible, cannulated implant having a flexible hingewith a reinforcing element embedded within the flexible hinge, inaccordance with one embodiment of the present patent application.

FIG. 12B shows a magnified view of the flexible hinge shown in FIG. 12A.

FIG. 13A shows a flexible, cannulated implant having a flexible hingewith reinforcing elements overlying top and bottom surfaces of theflexible hinge, in accordance with one embodiment of the present patentapplication.

FIG. 13B shows a magnified view of the flexible hinge shown in FIG. 13A.

FIG. 14A shows a flexible, cannulated implant having a flexible hingewith a first reinforcing element embedded within the flexible hinge, asecond reinforcing element overlying a top surface of the flexible hingeand a third reinforcing element overlying a bottom surface of theflexible hinge, in accordance with one embodiment of the present patentapplication.

FIG. 14B shows a magnified view of the flexible hinge shown in FIG. 14A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1A and 1B, in one embodiment, a flexible, cannulatedhammertoe implant 100 preferably includes a proximal stem 102 having aproximal conduit 104 extending therethrough, a distal stem 106 having adistal conduit 108 extending therethrough, and a flexible hinge 110 thatis located between and interconnects a distal end of the proximal stem102 and a proximal end of the distal stem 106. In one embodiment, theimplant is preferably a unitary polymer or plastic body that includesthe proximal stem, the distal stem, and the flexible hinge thatinterconnects the proximal and distal stems. As will be described inmore detail herein, the flexible hinge 110 preferably enables thehammertoe implant 100 to flex and/or bend so that after the implant hasbeen implanted in a toe, the distal stem 106 may rotate, swing and/ormove relative to the proximal stem 102. In one embodiment, the flexiblehinge 110 is thinner than the proximal and distal stems 102, 106 toprovide a region of the implant that is capable of flexing and/or toprovide a more flexible region of the implant.

In one embodiment, one or more of the proximal and distal stems 102, 106may include stabilizing features for securing the stems to boneincluding but not limited to threads, surface roughening and/or boneengaging fins. In one embodiment, the stabilizing features arepreferably provided on the outer surfaces of the proximal and distalstems.

In one embodiment, the implant and/or the flexible hinge may includestrengthening struts or a reinforcing element to prevent fracturing ofthe flexible hinge during flexing and bending. In one embodiment, thereinforcing element may be embedded inside the flexible hinge. In oneembodiment, the reinforcing element may be disposed over one or moresurfaces of the flexible hinge. In one embodiment, the reinforcingelement may be include a first reinforcing fabric embedded within aflexible hinge, with a second reinforcing fabric secured over one of thetop and bottom surfaces of the flexible hinge. In one embodiment, thereinforcing element may include a first reinforcing fabric embeddedwithin the flexible hinge, a second reinforcing fabric secured over atop surface of the flexible hinge, and a third reinforcing fabricsecured over a bottom surface of the flexible hinge.

In one embodiment, the flexible hammertoe implant 100 may be made ofmedical grade biocompatible materials that are typically used for makingsurgical implants including metals (e.g., titanium, stainless steel,alloys thereof), alloys, polymers (e.g., plastics, medical gradesilicone elastic polymers), and combinations of metals, alloys and/orpolymers. In one embodiment, the implant 100 is made of a combination ofmetal and polymer materials.

In one embodiment, the proximal stem 102 has a flat top surface 112, aflat bottom surface 114, and flat side surfaces 116, 118 that providethe proximal stem with a substantially square or rectangular shapedcross-section.

In one embodiment, the distal stem 106 has a flat top surface 120, aflat bottom surface 122, and flat side surfaces 124, 126 that providethe distal stem with a substantially square or rectangular shapedcross-section.

Referring to FIG. 2, in one embodiment, the flexible hinge 110 of theimplant 100 preferably includes a top side 128 of the hinge 110 definedby a first sloping sidewall 130 at the distal end of the proximal stem102, a second sloping sidewall 130 at the proximal end of the distalstem 106 (that opposes the first sloping sidewall 130), and a flat topsurface 134 that extends between and interconnects lower ends of thefirst and second sloping sidewalls 130, 132. The first sloping sidewall130, the second sloping sidewall, and the flat top surface 134 of thetop side 128 of the hinge 110 preferably define a V-shaped top side 128having a truncated, flat apex. In one embodiment, the flat top surface134 does not come to a point or apex, which enhances the strength of thehinge 110 and minimizes the likelihood that the hinge will fractureand/or crack during flexing and bending of the implant.

In one embodiment, when rotating the distal stem 106 of the implant 100in a counterclockwise direction R1 relative to the proximal stem 102,the second sloping surface 132 at the proximal end of the distal stem106 may abut against the first sloping surface 130 at the distal end ofthe proximal stem 102 for acting as a hard stop and limiting furthercounterclockwise rotation of the distal stem 106 relative to theproximal stem 102.

In one embodiment, the flexible hinge 110 of the implant 100 preferablyincludes a bottom side 136 defined by a first sloping sidewall 138 atthe distal end of the proximal stem 102, a second sloping sidewall 140at the proximal end of the distal stem 106 (that opposes the firstsloping sidewall 138), and a flat bottom surface 142 that extendsbetween and interconnects upper ends of the first and second slopingsidewalls 138, 140. The first sloping sidewall 138, the second slopingsidewall 140, and the flat bottom surface 142 of the bottom side 136 ofthe hinge 110 preferably define a V-shaped bottom side 136 having atruncated, flat apex. In one embodiment, the flat bottom surface 142does not come to a point or apex, which enhances the strength of thehinge 110 and minimizes the likelihood that the hinge will fractureand/or crack during flexing and bending.

In one embodiment, when rotating the distal stem 106 of the implant 100in a clockwise direction R2 relative to the proximal stem 102, thesecond sloping surface 140 at the proximal end of the distal stem 106may abut against the first sloping surface 138 at the distal end of theproximal stem 102 for acting as a hard stop and limiting furtherclockwise rotation of the distal stem 106 relative to the proximal stem102.

In one embodiment, the proximal conduit 104 that extends through theproximal stem 102 defines a first opening 144 in the first slopingsidewall 130, and the distal conduit 108 that extends through the distalstem 106 defines a second opening 146 in the second sloping sidewall132. The first and second openings 144, 146 in the sloping sidewalls arepreferably in alignment with one another when the implant is straight sothat an elongated pin (e.g., a Kirschner wire) may be passed through thealigned proximal and distal conduits 104, 108.

Referring to FIGS. 3A and 3B, in one embodiment, the implant 100 may beplaced in a straight configuration so that the proximal and distalconduits 104, 108 of the respective proximal and distal stems 102, 106are in alignment with one another (e.g., the proximal and distalconduits are aligned along a common axis A₁). After the proximal anddistal conduits are aligned, an elongated pin 150 (e.g., a sterilizedmetal pin) may be passed through the distal conduit 108 of the distalstem 106 and the proximal conduit 104 of the proximal stem 102. Theelongated pin 150 is preferably straight and desirably has a proximalend 152 and a distal end 154. The elongated pin may be used toimmobilize the joint to allow for post-operative healing. In oneembodiment, the elongated pin 150 may be a Kirschner wire (also referredto as a K-wire), which is a sterilized, sharpened, smooth metal (e.g.,stainless steel) pin. Introduced in 1909 by Martin Kirschner, the wiresare now widely used in orthopedics and other types of medical andveterinary surgery. Kirschner wires come in different sizes and are usedto hold bone fragments together (e.g., pin fixation) or to provide ananchor for skeletal traction. The pins are often driven into the bonethrough the skin (percutaneous pin fixation) such as by using a powertool or a hand drill. https://en.wikipedia.org/wiki/Kirschner_wire.

The elongate pin 150 may have different diameters. In one embodiment,the elongated pin 150 has a diameter of about 0.028-0.062 inches (0.7mm-1.6 mm). In one embodiment, the elongated pin has a diameter of about0.045 inches (1.1 mm) or 0.062 inches (1.6 mm).

In one embodiment, the elongated pin 150 preferably passes between thefirst and second sidewalls 130, 132 that define the topside 128 of theflexible hinge 110. The elongated pin 150 preferably passes through therespective first and second openings 144, 146 (FIG. 2) provided in theopposing first and second sidewalls 130, 132. In one embodiment, thefirst and second openings 144, 146 are preferably disposed between thetop side of the flexible hinge and the upper end of the implant 100.

Referring to FIGS. 4A-4B and 5A-5B, in one embodiment, the implant 100is desirably used to treat a toe T having a hammertoe deformity, wherebythe toe T includes a metatarsal bone MB, a proximal phalanx PP, a middlephalanx MP, and a distal phalanx DP. In one embodiment, a surgicalopening SO (FIG. 4B) may be formed in the top of the toe T to expose theproximal end of the middle phalanx MP and the distal end of the proximalphalanx PP.

In one embodiment, a distal implant hole is preferably formed in theproximal end face of the middle phalanx MP such as by using one or moredrill bits and a surgical drill. In one embodiment the drilled distalimplant hole may initially have a circular cross-section. In oneembodiment, a broaching tool may be inserted into the distal implanthole to re-shape the drilled distal implant hole from one having acircular cross-section to one having a square and/or rectangular shapedcross-section that is adapted to seat the square and/or rectangularshaped distal stem 106 of the implant. Squaring off the distal implanthole in the proximal end face of the middle phalanx MP preferablyprevents the implant 100 from rotating after the distal stem 106 of theimplant 100 has been inserted into the middle phalanx MP.

In one embodiment, a proximal implant hole is preferably formed in thedistal end face of the proximal phalanx PP such as by using one or moredrill bits and a surgical drill. In one embodiment the drilled proximalimplant hole may initially have a circular cross-section. In oneembodiment, a broaching tool may be inserted into the proximal implanthole to re-shape the drilled proximal implant hole from one having acircular cross-section to one having a square and/or rectangular shapedcross-section that is adapted to seat the square and/or rectangularshaped proximal stem 102 of the implant. Squaring off the proximalimplant hole in the distal end face of the proximal phalanx PPpreferably prevents the implant 100 from rotating after the proximalstem 102 of the implant 100 has been inserted into the proximal phalanxPP.

In one embodiment, after the distal stem 106 of the implant 100 has beeninserted into the squared-off distal hole formed in the middle phalanxMP and after the proximal stem 102 of the implant 100 has been insertedinto the squared-off proximal hole formed in the proximal phalanx PP,the elongated pin 150 is preferably utilized for securing the implant100 to the bones of the toe T. In one embodiment, in order to secure theimplant 100 in place, the distal end 154 of the elongated pin 150 ispreferably inserted into the opening 146 in the second sloping sidewall132 (FIG. 2) at the proximal end of the distal stem 106 of the implant100. The distal end 154 of the elongated pin 150 is preferably advancedin series in a distal direction designated DIR1 through the distalconduit 108 of the distal stem 106, beyond the distal end of the middlephalanx MP, and through the distal phalanx DP until the distal end 154of the elongated pin 150 is exposed outside the distal end of the toe T.

In one embodiment, after the distal end 154 of the elongated pin 150 isadvanced distally beyond the distal end of the toe T, the direction ofthe elongated pin is reversed for being advanced in the proximaldirection designated DIR2 through the proximal stem 102 of the implant100. In one embodiment, the proximal end 152 of the elongated pin 150 ispreferably inserted into the opening 144 in the first sloping sidewall130 (FIG. 2) at the distal end of the proximal stem 102 of the implant100. The proximal end 152 of the elongated pin 150 is preferablyadvanced in series in a proximal direction through the proximal conduit104 of the proximal stem 106, beyond the proximal end of the proximalphalanx PP, and into the distal head of the metatarsal bone MB.

The elongated pin 150 preferably secures the implant 100 to the bone andthe toe T, holds the implant 100 in a straight configuration duringhealing, and stabilizes the digital deformity post-operatively. In oneembodiment, the centrally placed elongated pin 150 may be removed about4-6 weeks after the completion of the surgical procedure to allow forflexion at the proximal interphalangeal joint.

Referring to FIGS. 6A and 6B, about four-six weeks following completionof a surgical procedure, the elongated pin 150 may be removed to allowthe implant 100 to flex. In one embodiment, the distal end 154 of theelongated pin 150 is grasped and pulled in the distal directiondesignated DIR1 for withdrawing the elongated pin from the bones of thetoe T and the implant 100.

Referring to FIG. 7A, in one embodiment, a flexible implant 100 isdesirably used to treat a toe T having a hammertoe deformity, wherebythe toe T includes a metatarsal bone MB, a proximal phalanx PP, a middlephalanx MP, and a distal phalanx DP. In other embodiments, the implantmay be placed between any two bones in a human or animal body to repaira joint and allow for post-operative flexibility, such as between twobones in a human hand. In one embodiment, a surgical opening SO may beformed in the top of the toe T to expose the proximal end of the middlephalanx MP and the distal end of the proximal phalanx PP.

In one embodiment, a distal implant hole is preferably formed in theproximal end face of the middle phalanx MP such as by using one or moredrill bits and a surgical drill. In one embodiment the drilled distalimplant hole may initially have a circular cross-section. In oneembodiment, a broaching tool may be inserted into the distal implanthole to re-shape the drilled distal implant hole from one having acircular cross-section to one having a square and/or rectangular shapedcross-section that is adapted to seat the square and/or rectangularshaped distal stem 106 of the implant 100. Squaring off the distalimplant hole in the proximal end face of the middle phalanx MPpreferably prevents the implant 100 from rotating after the distal stem106 of the implant 100 has been inserted into the middle phalanx MP.

In one embodiment, a proximal implant hole is preferably formed in thedistal end face of the proximal phalanx PP such as by using one or moredrill bits and a surgical drill. In one embodiment the drilled proximalimplant hole may initially have a circular cross-section. In oneembodiment, a broaching tool may be inserted into the proximal implanthole to re-shape the drilled proximal implant hole from one having acircular cross-section to one having a square and/or rectangular shapedcross-section that is adapted to seat the square and/or rectangularshaped proximal stem 102 of the implant. Squaring off the proximalimplant hole in the distal end face of the proximal phalanx PPpreferably prevents the implant 100 from rotating after the proximalstem 102 of the implant 100 has been inserted into the proximal phalanxPP.

In one embodiment, after the distal stem 106 of the implant 100 has beeninserted into the squared-off distal hole formed in the middle phalanxMP and the proximal stem 102 of the implant 100 has been inserted intothe squared-off proximal hole formed in the proximal phalanx PP, theelongated pin 150 (e.g., a K-wire) is preferably utilized for securingthe implant 100 to the bones of the toe T. The elongated pin 150 ispreferably straight and rigid and may be made of metals such asbiocompatible metals, stainless steel, titanium and/or alloys thereof.In one embodiment, in order to secure the implant 100 in place duringhealing, the implant 100 may be flexed so that the distal stem 106extends along an axis A₂ and the proximal stem 102 extends along an axisA₁ that defines an angle with the axis A₂ (e.g., not parallel). With thedistal stem 106 angulated relative to the proximal stem 102, the opening146 in the second sloping sidewall 132 (FIG. 2) of the hinge 110 isaccessible through the surgical opening SO, whereupon the distal end 154of the elongated pin 150 may be inserted into the opening 146. Thedistal end 154 of the elongated pin 150 is preferably advanced in seriesin a distal direction designated DIR1 through the distal conduit 108 ofthe distal stem 106, beyond the distal end of the middle phalanx MP, andthrough the distal phalanx DP until the distal end 154 of the elongatedpin 150 is exposed outside the distal end of the toe T.

Referring to FIGS. 7A and 7B, in one embodiment, after the distal end154 of the elongated pin 150 is advanced distally beyond the distal endof the toe T, the direction of the elongated pin may be reversed forbeing advanced through the proximal stem 102 of the implant 100 in theproximal direction designated DIR2 (FIG. 7B). In one embodiment, withthe proximal end 152 of the elongated pin 150 positioned within theV-shaped groove located above the flexible hinge 110, the implant isreturned from the flexed configuration shown in FIG. 7A to a straightconfiguration shown in FIG. 7B. In the straight configuration of FIG.7B, the proximal and distal stems 102, 106 extend along a common axisA₁. In one embodiment, the proximal end 152 of the elongated pin 150 isinserted into the opening 144 in the first sloping sidewall 130 (FIG. 2)of the hinge 110 (at the distal end of the proximal stem 102 of theimplant 100). Referring to FIGS. 7B and 7C, the proximal end 152 of theelongated pin 150 is preferably advanced in series in a proximaldirection DIR2 through the proximal conduit 104 of the proximal stem106, beyond the proximal end of the proximal phalanx PP, and into thedistal head of the metatarsal bone MB.

The elongated pin 150 preferably secures the implant 100 to the bone andthe toe T, holds the implant 100 in a straight configuration duringhealing, and stabilizes the digital deformity post-operatively.Referring to FIG. 7C, about four-six weeks following completion of asurgical procedure, the elongated pin 150 may be removed to allow theimplant 100 to flex. In one embodiment, the distal end 154 of theelongated pin 150 is grasped and pulled in the distal directiondesignated DIR1 for withdrawing the elongated pin from the bones of thetoe T and the implant 100.

Referring to FIG. 8, in one embodiment, after the elongated pin has beenremoved, the flexible hinge 110 of the implant 100 enables to distalstem 106 of the implant, which is anchored to the middle phalanx MP, torotate, swing and/or move relative to the proximal stem 102 of theimplant 100, which is anchored to the proximal phalanx PP.

Referring to FIG. 9, in one embodiment, a flexible, cannulated implant200 preferably includes a proximal stem 202 having a proximal conduit204 extending therethrough, a distal stem 206 having a distal conduit208 extending therethrough, and a flexible hinge 210 that is locatedbetween and interconnects a distal end of the proximal stem 202 and aproximal end of the distal stem 206. The implant may be implanted in thebones of a patient such as toe and finger bones. In one embodiment, theimplant 200 desirably comprises a unitary body including the proximaland distal stems and the flexible hinge. In one embodiment, the unitarybody may be molded and may be made of polymers or plastics. In oneembodiment, the proximal stem and the proximal conduit associatedtherewith have a greater length than the distal stem and the distalconduit associated therewith. The flexible hinge 210 preferably enablesthe implant 200 to flex and/or bend so that after the implant has beenimplanted in bone (e.g., between bones in a toe, between bones in afinger), the distal stem 206 (e.g., anchored to a middle phalanx MP) mayrotate, swing and/or move relative to the proximal stem 202 (anchored toa proximal phalanx PP).

In one embodiment, the implant 200 preferably includes a proximal stemprotective tube 260 that is adapted to be inserted into the proximalconduit 204 of the proximal stem 202. In one embodiment, the proximalstem 202 is made of a medical grade, biocompatible polymer and theproximal stem protective tube 260 is made of metal such as stainlesssteel or titanium. The proximal stem protective tube 260 made of metalpreferably prevents the proximal end 152 of an elongated pin 150 (FIG.7B) from piercing through the polymer or plastic proximal stem as theelongated pin is advanced proximally through the proximal conduit 204 ofthe proximal stem 202.

In one embodiment, the implant 200 preferably includes a distal stemprotective tube 262 that is adapted to be inserted into the distalconduit 208 of the distal stem 206. In one embodiment, the distal stem206 is made of a medical grade, biocompatible polymer and the distalstem protective tube 262 is made of metal such as stainless steel ortitanium. The distal stem protective tube 262 made of metal preferablyprevents the distal end 154 of an elongated pin 150 (FIG. 7B) frompiercing through the polymer distal stem 206 as the elongated pin isadvanced distally through the distal conduit of the distal stem 202.

Referring to FIG. 10, in one embodiment, the proximal stem protectivetube 260 is inserted into the proximal conduit 204 of the proximal stem202 of the implant 200, and the distal stem protective tube 262 isinserted into the distal conduit 208 of the distal stem 206. In oneembodiment, the proximal stem protective tube 260 has a length thatmatches the length of the proximal conduit 204 of the proximal stem 202,and the distal stem protective tube 262 has a length that matches thelength of the distal conduit 208 of the distal stem 206. In oneembodiment, the proximal stem protective tube 260 is longer than thedistal stem protective tube 262. In one embodiment, after assembly withthe stems, the respective protective tubes have central openings thatare aligned with the first and second openings 244, 246 located abovethe flexible hinge 210.

Referring to FIG. 11, in one embodiment, an elongated pin 250 is adaptedto pass through the proximal stem 202 and the distal stem 206 of theimplant 200 for securing the implant to bone for post-operative healing,and for holding the implant in a straight configuration during thepost-operative healing period. In one embodiment, the implant has aflexible hinge 210 including a first sloping sidewall 230 having anopening 244 aligned with the proximal conduit 204 and an opposing secondsloping sidewall 232 having an opening 246 aligned with the distalconduit 208. In one embodiment, the openings 244, 246 are preferablylocated above a top side of the hinge 210 so that the elongated pin islocated between the top side of the hinge 210 and an upper end 270 ofthe implant 200. As the elongated pin 250 is passed through the implant,the proximal stem protective tube 260 (disposed within proximal conduit204) and the distal stem protective tube 262 (disposed within distalconduit 208) desirably prevent sharp features on the elongated pin 250from scraping, scratching, marring, and/or damaging the implant 200,which could adversely impact the reliability, ruggedness and/orperformance of the implant 200. For example, a scratch formed in aconduit 204, 208 of a polymer implant may eventually result in theformation of a crack or fissure in the body of the implant, which mayhave a deleterious impact on the performance of the implant (e.g.,require the implant to be removed and replaced).

Referring to FIGS. 12A and 12B, in one embodiment, a flexible implant300 desirably includes a unitary body made of polymer materials having aproximal stem 302, a distal stem 306 and a flexible hinge 310 thatinterconnects the proximal and distal stems 302, 306 for enabling theproximal and distal stems to flex and bend relative to one another forproviding flexibility to a joint located between adjacent bones. In oneembodiment, the flexible implant 300 preferably includes a reinforcingelement 375 embedded within the flexible hinge 310 for enhancing thestructural integrity of the flexible hinge and preventing the flexiblehinge from fracturing when flexing and bending. In one embodiment, thereinforcing element 375 may be a fabric piece. In one embodiment, thereinforcing element 375 may be a mesh, such as a polyester mesh. In oneembodiment, the polyester mesh may be made of the polyester fabric soldunder the trademark DACRON. In other embodiments, other reinforcingfabrics may be used instead of polyester fabrics so long as they arecompatible with the polymer or plastic materials used to make theimplant 300.

Referring to FIGS. 13A and 13B, in one embodiment, a flexible implant400 desirably includes a unitary body made of polymer materials having aproximal stem 402, a distal stem 406 and a flexible hinge 410 thatinterconnects the proximal and distal stems 402, 406 for enabling theproximal and distal stems to flex and bend relative to one another forproviding flexibility to a joint located between adjacent bones. In oneembodiment, the flexible implant 400 preferably includes a firstreinforcing element 475A overlying a top surface of the flexible hinge410 and a second reinforcing element 475B overlying a bottom surface ofthe flexible hinge 410 for enhancing the structural integrity of theflexible hinge and preventing the flexible hinge from fracturing whenflexing and bending. In one embodiment, the first and second reinforcingelements 475A, 475B may be fabric pieces, a mesh, a polyester mesh, apolyester fabric sold under the trademark DACRON, and/or otherreinforcing fabrics may be used instead of polyester fabrics so long asthey are compatible with the polymer or plastic materials used to makethe implant 400.

Referring to FIGS. 14A and 14B, in one embodiment, a flexible implant500 desirably includes a unitary body made of polymer materials having aproximal stem 502, a distal stem 506 and a flexible hinge 510 thatinterconnects the proximal and distal stems 502, 506 for enabling theproximal and distal stems to flex and bend relative to one another forproviding flexibility to a joint located between adjacent bones. In oneembodiment, the flexible implant 500 preferably includes a firstreinforcing element 575A embedded within the flexible hinge 510, asecond reinforcing element 575B overlying a top surface of the flexiblehinge 510, and a third reinforcing element 575C overlying a bottomsurface of the flexible hinge 510 for enhancing the structural integrityof the flexible hinge and preventing the flexible hinge from fracturingwhen flexing and bending. In one embodiment, the reinforcing elements575A-575C may be fabric pieces, a mesh, a polyester mesh, a polyesterfabric sold under the trademark DACRON, and/or other reinforcing fabricsmay be used instead of polyester fabrics so long as they are compatiblewith the polymer or plastic materials used to make the implant 400.

The reinforcing elements shown and described in FIGS. 12A-12B, 13A-13B,and 14A-14B may be incorporated into any of the flexible implantsdisclosed in the present patent application.

In one embodiment, the implants disclosed herein may be used in the handand/or for hand digital implantation.

In one embodiment, the implants disclosed herein may be used to treathumans.

In one embodiment, the implants disclosed herein may be used to treatanimals having skeletal systems.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, which is only limited by thescope of the claims that follow. For example, the present inventioncontemplates that any of the features shown in any of the embodimentsdescribed herein, or incorporated by reference herein, may beincorporated with any of the features shown in any of the otherembodiments described herein, or incorporated by reference herein, andstill fall within the scope of the present invention.

What is claimed is:
 1. A flexible interphalangeal bone implantcomprising: a proximal stem having a proximal end, a distal end, and aproximal conduit having a length extending from the proximal end to thedistal end of said proximal stem, wherein said proximal conduit is openat both the proximal and distal ends of said proximal stem; a distalstem having a proximal end, a distal end, and a distal conduit having alength extending from the proximal end to the distal end of said distalstem, wherein said distal conduit is open at both the proximal anddistal ends of said distal stem; a flexible hinge interconnecting thedistal end of said proximal stem with the proximal end of said distalstem for allowing said proximal and distal stems to flex relative to oneanother, wherein said flexible hinge comprises a top side defined by afirst sloping sidewall at the distal end of said proximal stem, a secondsloping sidewall at the proximal end of said distal stem that opposessaid first sloping sidewall, and a flat top surface that extends betweenand interconnects lower ends of said first and second sloping sidewalls;a discrete proximal stem protective tube disposed within said proximalconduit of said proximal stem, wherein said proximal stem protectivetube has a length that matches the length of said proximal conduit; anda discrete distal stem protective tube disposed within said distalconduit of said distal stem, wherein said distal stem protective tubehas a length that matches the length of said distal conduit; wherein theproximal and distal stem protective tubes are sized and configured toreceive an elongated pin extending in series through said proximal stemprotective tube disposed within said proximal stem, said first slopingsidewall, said second sloping sidewall, and said distal stem protectivetube disposed within said distal stem; wherein said proximal stem, saiddistal stem, and said flexible hinge comprise a unitary structuremonolithically made of a polymer material, and wherein said proximalstem protective tube and said distal stem protective tube are made ofmetal.
 2. The flexible interphalangeal bone implant as claimed in claim1, further comprising an elongated pin extending through said distalstem protective tube disposed within said distal stem and said proximalstem protective tube disposed within said proximal stem.
 3. The flexibleinterphalangeal bone implant as claimed in claim 2, wherein saidelongated pin is selected from the group consisting of bone pins andKirschner wires.
 4. The flexible interphalangeal bone implant as claimedin claim 1, wherein said polymer material is selected from the groupconsisting of silicone elastic polymers and plastics and said metal isselected from the group consisting of biocompatible metals, titanium,titanium alloys, stainless steel, and stainless steel alloys.
 5. Theflexible interphalangeal bone implant as claimed in claim 1, whereinsaid proximal stem has a flat top surface, a flat bottom surface, andflat side surfaces that define a proximal stem structure having asubstantially square or rectangular shaped cross-section, and whereinsaid distal stem has a flat top surface, a flat bottom surface, and flatside surfaces that define a distal stem structure having a substantiallysquare or rectangular shaped cross-section.
 6. The flexibleinterphalangeal bone implant as claimed in claim 1, wherein said firstsloping sidewall, said second sloping sidewall and said flat top surfacedefine a V-shaped top side of said flexible hinge having a truncated,flat apex.
 7. The flexible interphalangeal bone implant as claimed inclaim 1, wherein said proximal conduit extending through said proximalstem defines a first opening in said first sloping sidewall, and whereinsaid distal conduit extending through said distal stem defines a secondopening in said second sloping sidewall that is aligned with said firstopening in said first sloping sidewall.
 8. The flexible interphalangealbone implant as claimed in claim 7, wherein said flexible implant isnormally in a straight configuration in which said proximal and distalconduits extend along a common axis, and wherein said flexible implantis moveable into a flexed configuration in which said proximal anddistal conduits extend along different axes that define an angle.
 9. Theflexible interphalangeal bone implant as claimed in claim 1, whereinsaid flexible implant further comprises a fabric reinforcing elementembedded within said flexible hinge or covering one or more surfaces ofsaid flexible hinge.
 10. The flexible interphalangeal bone implant asclaimed in claim 1, wherein said flexible hinge comprises a bottom sidedefined by a first bottom side sloping sidewall at the distal end ofsaid proximal stem, a second bottom side sloping sidewall at theproximal end of said distal stem that opposes said first bottom sidesloping sidewall, and a flat bottom surface that extends between andinterconnects upper ends of said first and second bottom side slopingsidewalls.
 11. The flexible interphalangeal bone implant as claimed inclaim 1, wherein said first bottom side sloping sidewall, said secondbottom side sloping sidewall, and said flat bottom surface of saidbottom side of said flexible hinge preferably define a V-shaped bottomside having a truncated, flat apex.
 12. The flexible interphalangealbone implant as claimed in claim 11, wherein when rotating said distalstem of said implant in a clockwise direction relative to said proximalstem, said second bottom side sloping surface abuts against said firstbottom side sloping surface for acting as a hard stop and limitingfurther rotation of said distal stem relative to said proximal stem.